Generally, the routing you describe is correct. I tapped into the switched power feed to the USB and accessory plugs, which is under the plastic that covers the center console area. The power cable from the CAN plug to the center console is “visible”, but hung underneath the dash area so you’d have to stick your head under the steering wheel to actually see it.
Coax cable from the PMP to the front camera runs back into that area behind the touch screen, over to passenger side, and up to A-pillar all hidden in the available housings. All the plastic housings around the floor, console and yacht floor are super easy to remove without risk of breaking plastic or clips.
In order to avoid drilling, I left a tiny (less than 6″) length of the coax visible from the extreme right of the dash before it runs into the A-pillar cover. This is so close to invisible that you have to know it’s there and really look for it to see it. It’s a black cable tucked into a small seam between two black plastic dash sections. Once into the A-pillar, it’s a fairly easy run through to the mirror housing. It was a bit tough to pull the mirror housing off – I did crack one clip but it fits back together with no looseness or loss of function (lesson learned – gentle gentle gentle with these bits!). The main thing with running along the A-pillar (VERY IMPORTANT) is to be absolutely sure that the new cable does not interfere with the airbag’s deployment path.
The coax run to the rear was pretty easy, except for the part where you need to run through the gromment/flex tube between the rear hatch frame and the hatch. Verrrrrry tight fit, but with a lot of patience it does get through. I did drill one hole at the hatch, as it would have been very difficult without doing so.
As to skill level, I’d say that if you understand basic electrical circuits and have a lot of patience to do it neatly and fish the cables through the tough spots, it’s not that tough. There are two sections where cable runs very close to airbags, so very important to have a sense of how they deploy so that your cable does not interfere with them.